Three colors are required in order to set and stabilize a color location. Each of these individual colors is described by three color valencies XYZ. The mixing of three colors is uniquely determined by a system of equations including three equations and three unknowns.
With regard to their luminous characteristic, luminous systems based on three individual colors are not satisfactory for applications in lighting engineering; in particular, a viewer of such a luminous characteristic feels it to be unpleasant.
Consequently, more than three individual colors can be used in luminous systems. An overdetermined system of equations results when more than three individual colors are mixed for a color location.
Different luminous means, in particular light-emitting diodes and/or combinations of light-emitting diodes of various wavelengths are used as luminous sources in a luminous system.